Atleast. Alot. Afew. Abit. Bestfriend.
Why did we start mashing words together? "Alot" has been around for a while, but now folks are saying "I took afew hours off" and "it was abit cold outside." There's no way autocorrect is going this as they aren't correct.
"Bestfriend" is a relatively new one, I guess influenced by "girlfriend"/"boyfriend." Compared to the others it's less intolerable.
Edit: I forgot "aswell"!